ON   MEMORY 


THE     SPECIFIC    ENERGIES     OF    THE 
NERVOUS    SYSTEM 


PROF.   EWALD    HERING 


THIRD  EDITION 


CHICAGO 

THE  OPEN  COURT  PUBLISHING  COMPANY 

LONDON  AGENTS 

Kkgan  Paul,  Trench,  Trubner  &  Co.,  Ltd. 

1902 


Ei)t  ILafetcfte  ^rtea 

DONNELLEY  &  SONS  COMPANY 
CHICAGO 


BF 
37!    . 


MEMORY  AS  A  GENERAL  FUNCTION 
OF  ORGANISED  MATTER.* 


WHEN  a  scientist  leaves  behind  him  his  own  spe- 
cial province  of  inquiry,  to  make  an  excursion 
into  the  realm  of  philosophy,  he  may  cherish  the  hope 
of  solving  the  great  problem  which  underlies  the  minor 
questions  to  which  he  has  devoted  his  life,  but  he 
must  be  prepared  for  being  secretly  discredited  with 
those  of  his  colleagues  who  still  remain  quietly  at  work 
with  the  subjects  of  their  specialty,  and  at  the  same 
time  must  expect  the  mistrust  of  the  rightful  represen- 
tatives of  the  empire  of  speculation.  He  runs  the  risk 
of  losing  his  reputation  with  the  former  and  of  gaining 
nothing  with  the  latter. 

The  subject  for  which  I  ask  your  attention  on  this 
occasion  is  a  most  alluring  one  ;  but  in  accordance 
with  what  I  have  just  said,  it  is  not  my  intention  to 
abandon  the  domain  of  natural  science  to  which  my 
studies  have  been  devoted,  but  only  to  attempt  to  reach 

*  An  address  delivered  before  the  Imperial  Academy  of  Sciences,  at 

Vienna,  May  30,  1S70. 


2  MEM  OR  V. 

a  higher  ground  from  which  we  may  enjoy  a  freer  and 
more  general  survey. 

It  will  seem  in  the  course  of  this  paper  as  though 
I  am  not  always  faithful  to  this  purpose  ;  for  I  shall 
often  have  occasion  to  tarry  in  the  province  of  psy- 
chology. Consequently,  for  my  own  justification,  al- 
low me  to  point  out  the  extent  to  which  psychological 
inquiries  form,  not  only  an  allowable,  but  also  an  in- 
dispensable accompaniment  of  physiological  research. 

The  animal  human  organism  with  its  material 
mechanism  is  the  subject  of  physiology.  But  con- 
sciousness is  a  simultaneous  datum.  Besides  the  mov- 
ing of  the  atoms  of  the  brain  according  to  certain  laws, 
the  inner  life  of  our  soul  is  woven  of  sensations  and 
conceptions,  of  feeling  and  will. 

Everyone  experiences  this  in  himself;  and  it  is  a  fact 
also  which  beams  forth  from  the  faces  of  his  fellow- 
beings.  It  breathes  in  the  life  of  all  higher  organised 
animals,  and  even  the  simplest  creatures  bear  some 
vestiges  of  it.  Who  can  fix  the  limit  of  empsychosis 
in  the  empire  of  organic  nature  ? 

In  the  face  of  such  a  dual  aspect  of  organic  life 
what  can  physiology  best  do  ?  Shall  science  be  blind- 
folded on  the  one  side,  in  order  the  better  to  compre- 
hend the  other  ? 

As  long  as  a  physiologist  is  a  mere  physicist — and 
I  use  the  word  physicist  now  in  its  most  comprehensive 
sense — his  method  of  inquiring  into  organic  nature  is 
altogether  one  sided.    But  it  is  justly  so.    As  a  crystal 


MEMOR  Y.  3 

is  to  the  mineralogist,  so  to  the  physiologist  of  this 
class  is  a  man  or  an  animal^a  mere  lump  of  matter. 
An  animal  feels,  of  course,  pleasure  and  pain,  and  with 
the  material  phenomena  of  the  human  body  mental 
emotions  are  connected  ;  but  that  is  no  reason  why  a 
physicist  should  take  a  different  view  of  the  corporeal 
existence  of  man,  who  to  him  remains  a  compound  of 
matter  subject  to  the  same  irrefragable  laws  as  stones 
and  plants  ;  like  a  machine,  his  motions  are  causally 
connected  with  each  other  and  dependent  upon  their 
surroundings. 

Neither  sensation  nor  conception  nor  conscious  will 
can  form  a  link  in  the  chain  of  the  material  processes 
of  which  the  physical  life  of  organisms  consists.  When 
I  answer  a  question,  the  initial  material  process  is  con- 
ducted from  the  organ  of  hearing  by  sensory  nerve- 
fibres  to  the  brain,  and  must  pass  through  it  as  a  ma- 
terial process  in  order  to  reach  the  motor  nerves  of  the 
organ  of  speech.  It  cannot,  after  having  arrived  at  a 
certain  spot  in  the  brain,  enter  into  something  imma- 
terial, in  order  to  be  re-transformed,  in  some  other 
place  of  the  brain,  into  another  material  process.  A 
caravan  in  the  desert  might  just  as  well  enter  the  oasis 
of  a  mirage,  to  return  thence  after  a  refreshing  rest 
into  the  actual  desert. 

Such  is  the  physiologist,  so  far  as  he  is  a  physicist. 
He  stands  behind  the  stage  and  carefully  observes  the 
working  of  the  machinery  and  the  movements  of  the 
actors,  but  he  misses  the  meaning  of  the  action,  which 


4  MEMORY. 

a  spectator  readily  understands.  Now,  should  a  phys- 
iologist never  be  allowed  to  change  his  point  of  view? 

True,  his  object  is  not  to  understand  a  world  of 
concepts,  but  a  world  of  realities.  Nevertheless,  if 
now  and  then  he  changes  his  point  of  observation  and 
looks  at  things  from  the  other  side,  or  at  least  accepts 
from  trustworthy  observers  the  results  of  their  expe- 
rience, he  will  derive  much  benefit  from  such  an  at- 
titude and  will  better  comprehend  both  the  apparatus 
he  is  studying  and  its  methods  of  working. 

For  this  very  reason  psychology  is  an  indispens- 
able auxiliary  of  physiology.  If  the  latter  science  has 
hitherto  not  made  much  use  of  the  former,  it  has  not 
been  wholly  the  fault  of  physiology.  Psychology  has 
only  lately  worked  her  fields  with  the  plough  of  induc- 
tion, and  it  is  only  in  such  a  soil  that  the  fruits  can  be 
raised  for  which  the  physiologist  has  most  need. 

The  neurologist  is  thus  placed  between  the  phys- 
icist and  the  psychologist.  The  physicist  regards  the 
causal  continuity  of  material  processes  as  the  basis  of 
his  inquiry  ;  the  thoughtful  psychologist  seeks  for  the 
laws  of  conscious  life  :  and  in  so  doing  works  accord- 
ing to  the  rules  of  inductive  methods,  assuming  the  va- 
lidity of  an  inalterable  order.  Now,  if  the  physiologist 
learns  from  simple  self-observation  that  conscious  life 
is  dependent  upon  his  bodily  functions,  and  vice  versa 
that  his  body  to  some  extent  is  subject  to  his  will,  he 
has  only  to  assume  that  this  interdependence  of  mind  and 
body  is  arranged  according  to  certain  laws  and  the  link 


MEMORY  5 

is  found  which  connects  the  science  of  matter  with  the 
science  of  consciousness. 

Thus  considered,  phenomena  of  consciousness  ap- 
pear to  be  functions  of  material  changes  of  organised 
substance,  and  vice  versa.  As  I  wish  to  avoid  all  mis- 
conceptions, let  me  mention  (although  it  is  included 
in  the  term  function)  that  the  converse  of  this  asser- 
tion means  that  material  processes  of  the  cerebral  sub- 
stance also  appear  to  be  functions  of  the  phenomena 
of  consciousness.  For  if  two  variables  are  dependent 
upon  each  other,  according  to  certain  laws,  a  change 
of  the  one  demanding  a  change  of  the  other,  and  vice 
versa,  the  one  is  called  a  function  of  the  other. 

This  does  not  mean  that  the  two  variables,  matter 
and  consciousness,  are  connected  with  each  other  as 
cause  and  effect  ;  for  we  do  not  know  anything  about 
that.  Materialism  explains  consciousness  as  the  out- 
come of  matter,  idealism  takes  the  opposite  view,  and 
a  third  position  might  postulate  the  identity  of  spirit 
and  matter.  The  physiologist,  as  such,  should  not 
meddle  with  such  questions. 

Aided  by  this  hypothesis  of  a  functional  connex- 
ion between  spiritual  and  material  facts,  modern  phys- 
iology is  enabled  to  bring  the  phenomena  of  conscious- 
ness within  the  domain  of  its  inquiry,  without  leaving 
the  terra  firma  of  scientific  method.  The  physiolo- 
gist, as  a  physicist,  observes  how  a  beam  of  light,  a 
wave  of  sound,  or  a  vibration  of  heat  affects  the  organs 
of  sensation  j  how  they  enter  the  nerves,  are  trans- 


6  MEMORY. 

formed  into  an  irritation  of  the  nerve-fibres  and  con- 
ducted to  the  brain-cells.  Here  he  loses  all  trace  of 
them.  On  the  other  hand,  he  observes  a  spoken  word 
coming  from  the  mouth  of  a  speaking  person  ;  he  sees 
the  person  move  his  limbs,  and  finds  these  movements 
are  caused  by  muscular  contractions  produced  through 
motor  nerves  irritated  by  the  nerve-cells  of  the  central 
organs.  Here  again  he  is  at  his  v/it's  end.  The  bridge 
which  should  lead  him  from  the  irritated  sensory  nerve 
to  the  irritated  motor  nerve,  is  indicated  in  the  laby- 
rinthian  connexions  of  the  nerve-cells,  but  he  lacks  a 
clue  to  the  infinitely  involved  processes  which  are  in- 
terposed in  this  place.  It  is  here  the  physiologist  suc- 
cessfully changes  his  point  of  view.  Here  matter  no 
longer  reveals  the  secret  to  his  inquiring  glance  ;  but 
he  finds  it  in  the  mirror  of  consciousness,  not  directly, 
but  indirectly  and  figuratively — yet  in  lawful  connex- 
ion with  what  he  inquires  into.  Here,  in  observing 
how  one  idea  replaces  another,  how  from  sensations 
conception  rises,  and  how  from  conceptions  ?f77/ starts, 
how  emotions  and  thoughts  interweave,  he  will  sup- 
pose that  there  is  a  corresponding  series  of  intercon- 
nected material  processes  accompanying  the  whole 
action  of  conscious  life  according  to  the  law  of  the 
functional  interdependence  of  matter  and  conscious- 
ness. 

After  this  introduction  I  may  venture  to  combine 
under  one  point  of  view  a  long  series  of  phenomena 
which   are   apparently  widely  separated   and   belong 


MEMORY.  7 

partly  to  the  conscious,  partly  to  the  unconscious  life, 
of  organic  nature  :  these  we  shall  consider,  compre- 
hensively, as  the  results  {Aeusserungeri)  of  one  and  the 
same  faculty  of  organised  matter,  viz.,  memory,  or  the 
faculty  of  reproduction. 

Memory,  as  generally  understood,  is  merely  the 
faculty  of  voluntarily  reproducing  ideas  or  a  series  of 
ideas.  But  if  faces  and  events  of  past  days  appear, 
uncalled  for,  and  take  possession  of  our  consciousness, 
should  we  not  also  call  this,  with  the  same  right,  re- 
membering ?  We  are  justly  entitled  to  include  in  the 
concept  of  memory  all  involuntary  reproductions  of 
sensations,  conceptions,  emotions,  and  aspirations.  In 
doing  so,  memory  becomes  an  original  faculty,  being 
at  once  the  source  and  unification  of  all  conscious  life. 

It  is  well  known  that  sensuous  perceptions,  if  con- 
stantly repeated  for  a  time,  are  impressed  into  what  we 
call  the  memory  of  the  senses,  in  such  a  way  that  often 
after  hours,  and  even  after  we  have  been  busy  with  a 
hundred  other  things,  they  suddenly  return  into  con- 
sciousness in  the  full  sensuous  vivacity  of  their  original 
perception.  We  thus  experience  how  whole  groups 
of  sensations,  properly  regulated  in  their  spatial  and 
and  temporal  connexions,  are  so  vividly  reproduced  as 
to  be  like  reality  itself.  This  clearly  shows  that  after 
the  extinction  of  conscious  sensations,  some  material 
vestiges  still  remain  in  our  nervous  system,  implying 
a  change  of  its  molecular  and  atomic  structure,  by 
which  the  nervous  substance  is  enabled  to  reproduce 


8  MEM  OR  Y. 

such  physical  processes  as  are  connected  with  the  corre- 
sponding psychical  processes  of  sensations  and  percep- 
tions. 

Every  one  can  observe  in  his  daily  and  hourly  ex- 
perience such  phenomena  of  sense-memory,  although 
in  fainter  forms.  Consciousness  produces  legions  of 
more  or  less  faded  memory-pictures  {Erinnerungsbilder) 
of  former  sensuous  perceptions.  They  are  partly  called 
in  voluntarily,  and  they  partly  crowd  in  spontaneously. 
Faces  of  absent  persons  come  and  go  as  pale  and  vol- 
atile shadows,  and  sounds  of  melodies  which  have  long 
died  away  haunt  us,  if  not  audibly,  yet  perceptibly. 

Of  many  things  and  events,  especially  if  they  have 
been  perceived  only  once  or  very  superficially,  merely 
single,  unusually  striking  qualities  are  reproducible ;  of 
other  things  only  those  qualities  are  reproducible  which 
have  been  remarked  on  former  occasions,  our  brain 
being  in  this  way  prepared  for  their  reception.  Such 
are  responded  to  more  strongly  and  enter  consciousness 
more  easily  and  energetically.  Thus  their  ability  of 
being  reproduced  increases.  In  this  way,  what  is  com- 
mon to  many  things  and  hence  has  been  most  fre- 
quently perceived,  will  by  and  by  be  so  reproducible 
as  to  be  easily  called  forth  by  a  slight  internal  impulse, 
without  any  exterior  and  real  stimulus.  Such  a  sen- 
sation, which  is,  as  it  were,  produced  internally,  for 
instance,  the  idea  of  white,  is  not  of  the  same  vivacity 
as  the  sensation  of  white  color  externally  produced  by 
white  light.     But  it  is,  after  all,  essentially  the  same. 


MEMORY.  9 

being  a  weak  repetition  of  the  same  material  brain- 
process  and  of  the  same  conscious  sensation.  Thus 
the  idea  of  white  is  an  almost  imperceptibly  weak  per- 
ception. 

In  this  way  the  qualities  which  are  common  to 
many  things  are,  as  it  were,  separated  from  them  in 
entering  our  memory.  They  attain  an  independent  ex- 
istence in  consciousness  as  concepts  or  ideas,  and  the 
whole  rich  world  of  our  concepts  and  ideas  is  con- 
structed of  these  materials  of  memory. 

It  is  easily  seen  that  memory  is  not  so  much  a  fac- 
ulty of  conscious  as  of  unconscious  life.  What  was 
conscious  to  me  yesterday  and  again  becomes  con- 
scious to  me  to-day,  where  has  it  been  in  the  interim? 
It  did  not  exist  as  a  fact  of  consciousness,  and  yet  it 
returned.  Our  concepts  appear  on  the  stage  of  con- 
sciousness only  transiently ;  they  quickly  disappear  be- 
hind the  scenes,  to  make  place  for  others.  Only  on 
the  stage  are  they  conceptions,  as  an  actor  is  king  only 
on  the  stage.  As  what  do  they  remain  behind  the 
scenes  ?  For  that  they  exist  somehow  we  know  ;  a  cue 
only  is  needed  to  make  them  reappear.  They  do  not 
continue  as  conceptions,  but  as  certain  dispositions  of 
the  nervous  substance  {Stimynung  der  Nervensubstanz) 
by  virtue  of  which  the  same  sound  that  was  produced 
yesterday  can  again  be  evoked  to-day. 

Innumerable  reproductions  of  organic  processes  in 
our  cerebral  substance  constantly  combine  with  each 
other,  according  to  certain  laws,  each  in  its  turn  stimu- 


lo  MEMORY. 

lating  another.  But  the  phenomenon  of  consciousness 
is  not  necessarily  joined  with  each  link  of  such  a  series 
of  processes.  Accordingly,  chains  of  conceptions  some- 
times seem  to  lack  proper  connexions,  when  conveyed 
to  the  cerebral  substance  through  processes  unaccom- 
panied by  consciousness.  Therefore,  also,  a  long  se- 
ries of  ideas  may  follow  the  correct  logical  order  and 
have  a  proper  organic  structure,  although  the  differ- 
ent premises  that  are  indispensable  to  such  combina- 
tion do  not  become  conscious  at  all.  Some  ideas 
emerge  from  unconscious  life  into  consciousness,  with- 
out being  connected  with  any  conscious  conception 
whatever;  others  sink  into  unconsciousness  without 
ever  having  been  connected  with  conscious  ideas. 

Between  what  I  am  to-day  and  what  I  was  yester- 
day, a  gap  of  unconsciousness  lies,  the  nocturnal 
sleep  ;  and  it  is  only  memory  which  spans  a  bridge  be- 
tween my  to-day  and  my  yesterday.  Who  can  hope  to 
unravel  the  manifold  and  intricately  intertwined  tis- 
sues of  the  inner  life  by  simply  following  the  threads 
of  consciousness?  You  may  as  well  gather  your  infor- 
mation about  the  rich  organic  life  of  the  oceanic  world 
from  those  few  forms  which  now  and  then  emerge 
from  the  surface  of  the  sea  merely  to  disappear  again 
into  the  depths  of  the  ocean. 

Thus  the  cause  which  produces  the  unity  of  all 
single  phenomena  of  consciousness  must  be  looked  for 
in  unconscious  life.  As  we  do  not  know  anything  of 
this  except  what  we  know  from  our  investigations  of 


MEMORY.  II 

matter,  and  since  in  a  purely  empirical  consideration, 
matter  and  the  unconscious  must  be  regarded  as  iden- 
tical, the  physiologist  may  justly  define  memory  in  a 
wider  sense  to  be  a  faculty  of  the  brain,  the  results  of 
which,  to  a  great  extent,  belong  to  both  consciousness 
and  unconsciousness. 

Every  perception  of  an  object  in  space  is  a  highly 
complicated  process.  For  instance,  a  white  ball  sud- 
denly looms  up  before  my  eyes.  It  is  necessary,  not 
only  to  convey  the  perception  of  white  to  conscious- 
ness, but  also  the  circular  periphery  of  the  visible  ball ; 
moreover,  its  globular  form,  as  it  is  recognised  from 
the  distributions  of  light  and  shade  ;  then  the  exact 
distance  from  my  eyes  must  be  considered,  and  from 
this  we  form  an  estimate  concerning  its  size.  What 
an  apparatus  of  sensations,  perceptions,  and  conclu- 
sions is  apparently  necessary  for  accomplishing  all  this  ! 
And  yet  the  actual  perception  of  the  sphere  is  per- 
formed in  a  few  seconds,  without  my  becoming  con- 
scious of  the  single  processes  which  construct  the 
whole;  the  result  enters  my  consciousness  complete. 

The  nervous  substance  faithfully  preserves  the 
records  of  processes  often  performed.  All  functions 
necessary  for  correct  perception,  which  at  first  operated 
slowly  and  with  difficulty  with  the  constant  help  of  con- 
sciousness, are  afterward  reproduced  summarily  and 
without  an  intensity  sufficient  to  push  each  single  link 
of  the  chain  beyond  the  threshold  of  consciousness. 
Such  chains  of  unconscious  nerve-processes,  which  at 


12  MEMORY. 

last  end  in  a  link  accompanied  with  consciousness, 
have  been  called  unconscious  chains  of  perceptions,  or 
unconscious  conclusions ;  a  name  which  is  justifiable 
from  the  standpoint  of  psychology.  For  psychology 
might  frequently  lose  sight  of  the  soul,  if  unconscious 
states  were  not  taken  into  consideration.  To  a  phys- 
ical consideration,  however,  unconscious  and  material 
mean  the  same,  and  a  physiology  of  the  unconscious  is  no 
philosophy  of  the  unconscious.  * 

Almost  all  movements  which  man  performs  are  the 
result  of  long  and  difficult  practice.  The  harmonious 
co-operation  of  the  different  muscles,  the  exactly 
gauged  amount  of  work  which  each  one  must  contrib- 
ute to  the  common  labor,  must  be  learned  for  most 
movements  with  great  trouble.  How  slowly  a  begin- 
ner at  the  piano  finds  the  single  notes,  the  eye  direct- 
ing his  fingers  to  the  different  keys,  and  then  how 
marvellous  is  the  play  of  the  virtuoso.  With  the  swift- 
ness of  thought  each  note  finds  an  easy  passage  through 
the  eye  to  the  finger,  to  be  performed  correspondingly. 
One  quick  glance  at  the  music  suffices  to  transform 
into  sound  a  whole  series  of  chords  ;  and  a  melody 
which  has  been  sufficiently  practised  may  be  played 
while  the  player's  attention  is  directed  to  other  sub- 
jects. 

In  such  a  case  the  will  no  longer  directs  each  sin- 
gle finger  to  produce  the  desired  movements,  and  no 
close  attention  is  needed  to  watch  the  whole  execution 

*  Refers  to  Von  Hartmann's  Philosophy  of  the  Unconscious.— Tr. 


MEMORY.  13 

carefully.  Will  is  only  commander-in-chief.  Will 
issues  an  order,  and  all  the  muscles  act  accordingly. 
They  continue  to  work  as  long  as  they  move  in  their 
customary  tracks,  till  a  slight  hint  of  the  will  prescribes 
some  other  direction. 

This  would  be  impossible,  if  those  parts  of  the  cen- 
tral nervous  system  which  bring  about  the  movement, 
were  not  capable  of  reproducing  entire  series  of  states 
of  irritation.  When  they  have  been  previously  prac- 
tised, under  a  constant  accompaniment  of  conscious- 
ness, they  can  be  called  forth,  as  it  were,  independ- 
ently, on  the  slightest  impulse  of  consciousness,  being 
executed  more  quickly  and  more  perfectly,  the  oftener 
the  reproductions  have  been  repeated.  All  this  is  pos- 
sible only  if  they  remember  what  they  did  before.  Our 
perceptive  faculty  would  forever  remain  in  its  lowest 
stage,  if  we  should  consciously  construct  every  single 
perception  from  the  given  single  materials  of  sensa- 
tion. Our  voluntary  motions  would  never  surpass  the 
awkwardness  of  a  child,  if  in  every  case  we  should  re- 
incite  with  conscious  will  the  different  single  impulses 
and  reproduce  over  again  all  our  single  conceptions  ; 
or,  to  state  it  briefly,  if  the  nervous  motor  system 
were  not  endowed  with  memory,  viz.,  an  unconscious 
memory.  What  is  called  force  of  habit,  is  the  strength 
of  this  memory. 

It  is  to  memory  that  we  owe  all  we  a^-e  and  have. 
Ideas  and  concepts  are  products  of  it;  each  percep- 
tion,   each   thought,    each    motion   is    carried    by  it. 


14  MEMORY. 

Memory  unites  all  the  innumerable  single  phenomena 
of  consciousness  into  one  entirety ;  and  as  our  body 
would  be  dispersed  into  myriads  of  atoms,  if  it  were 
not  held  together  by  the  attraction  of  matter,  so,  but 
for  the  binding  power  of  memory,  consciousness  would 
be  dissolved  into  as  many  fragments  as  there  are  mo- 
ments. 

We  have  seen  that  only  a  part  of  the  reproductions 
of  organic  processes,  as  effected  by  the  memory  of 
nervous  substance,  enters  our  consciousness ;  no  less 
unimportant  parts  remain  unconscious.  And  the  same 
may  be  proved  by  numerous  facts  relating  to  parts  of 
the  nervous  system  which  are  exclusively  subservient 
to  the  unconscious  processes  of  life.  For  the  memory 
or  reproductive  faculty  of  the  so-called  sympathetic 
nervous  system  is  by  no  means  weaker  than  that 
of  the  brain  and  the  spinal  cord.  Medical  art,  to  a 
great  extent,  makes  good  use  of  this. 

In  concluding  this  part  of  my  investigation,  let  me 
leave  the  subject  of  nervous  substance  for  a  moment 
in  order  to  take  a  cursory  view  of  other  organic  mat- 
ter, where  we  meet  with  the  same  reproductive  fac- 
ulty, but  in  a  simpler  form. 

Daily  experience  teaches  us  that  muscles  grow 
stronger  the  oftener  they  are  used.  Muscle-fibre,  which 
in  the  beginning  but  feebly  responded  to  the  irritation 
of  a  motor  nerve,  works  with  more  energy  the  oftener 
it  is  irritated,  after  proper  intervals  of  rest.  After  each 
single  action  it  becomes  more  capable  of  action  ;  it 


MEMORY.  15 

grows  fitter  for  the  repetition  of  the  same  work  and 
better  adapted  to  the  reproduction  of  the  same  organic 
process.  Pari  passu,  its  size  increases,  because  it  as- 
similates more  than  in  a  state  of  constant  rest. 

This  is  the  very  same  faculty  of  reproduction  whose 
action  in  nervous  substance  is  so  complicated  ;  here  it 
is  observable  in  its  simplest  form,  and  easier  under- 
stood as  a  physical  process.  And  what  is  more  accu- 
rately known  of  muscle-substance,  is  more  or  less 
clearly  demonstrable  of  the  substances  of  all  other 
organs.  Everywhere  we  find  an  increased  activity 
with  adequate  pauses  of  rest  accompanied  by  an  in- 
creased strength  of  action  ;  and  organs  which  are  used 
oftener  in  the  animal  economy  also  grow  in  size  by 
increased  assimilation.  But  this  increase  of  mass  not 
only  means  an  aggrandisement  and  growth  of  the  single 
cells  or  fibres  of  which  the  organ  is  composed,  but  also 
an  augmentation  of  their  number.  A  cell  grown  to  a 
certain  size  divides  into  filial  cells,  which  inherit,  in  a 
greater  or  less  degree,  the  qualities  of  the  parental 
cell,  and  accordingly  represent  repetitions  of  it.  This 
growth  and  augmentation  of  cells  is  one  of  the  differ- 
ent functions  which  are  characteristic  of  organised 
matter.  These  functions  are  not  only  interior  phe- 
nomena of  the  cell-substance,  not  only  certain  changes 
or  motions  of  its  molecular  structure,  but  they  also  be- 
come externally  visible  as  a  modification  of  form,  an 
aggrandisement  of  size  or  a  division  of  the  cell.  Thus 
the  reproductive  function  of  a  cell  is  manifested  also  as 


i6  MEMOR  Y. 

a  reproduction  of  the  cell  itself.  This  is  most  obvious 
in  plants  ;  the  chief  function  of  their  cells  is  the  work 
of  growth,  while  in  animal  organisms  other  functions 
are  predominant. 

Now,  let  me  finally  consider  the  phenomena  in 
which  the  power  of  memory  in  organised  matter  is  most 
striking. 

On  the  basis  of  numerous  facts,  we  may  justly  as- 
sume that  even  such  qualities  of  an  organism  can  be 
transferred  to  its  posterity  as  have  not  been  inherited 
but  have  been  acquired  under  peculiar  circumstances 
of  life.  Thus,  every  organic  being  endows  its  germs 
with  some  small  inheritance  which  has  been  acquired 
during  the  individual  life  of  the  parentaLorganism  and 
is  added  to  the  total  legacy  of  the  race. 

Considering  that  properties  are  inherited  which 
have  been  developed  in  different  organs  of  the  paren- 
tal being,  it  has  appeared  highly  enigmatic  to  investi- 
gators how  these  same  organs  could  have  influenced  a 
germ  developed  in  a  distant  place.  So  it  has  happened 
that  as  a  solution  of  this  problem  mystic  views  have 
often  been  propounded. 

The  subject  may  be  best  comprehended  from  a 
physiological  standpoint,  in  this  way. 

The  nervous  system,  in  spite  of  its  being  a  com- 
pound of  many  thousands  of  cells  and  fibres,  never- 
theless forms  one  coherent  entirety.  It  is  in  communi- 
cation with  all  organs  ;  according  to  recent  histolog- 
ical researches,  it  is  believed  that  it  is  connected  with 


MEMOR  V.  17 

every  cell  of  the  more  important  organs,  either  directly 
or  at  least  indirectly  through  a  living,  irritable,  and 
therefore  conducting  cell-substance.  Through  this 
connexion,  all  organs  are  more  or  less  interdependent, 
so  that  the  destinies  of  the  one  are  re-echoed  in  the 
others ;  and  any  irritation  effected  in  any  one,  is  trans- 
fused, be  it  ever  so  feebly,  to  the  remotest  parts  of  the 
body.  In  addition  to  this  delicate  connexion  of  all  parts 
by  the  nervous  tissue,  another,  but  slower  and  more 
sluggish,  connexion  is  effected  by  means  of  the  circu- 
lating fluids. 

We  notice  further  that  the  developmental  process 
of  the  germs  destined  to  attain  independent  existence, 
exercises  a  powerful  reaction  on  both  the  conscious 
and  unconscious  life  of  the  whole  organism.  And  this 
is  a  hint  that  the  organ  of  germination  is  in  a  closer 
and  more  momentous  connexion  with  the  other  parts, 
especially  with  the  nervous  system,  than  any  other  or- 
gan. Conversely,  the  conscious  and  unconscious  des- 
tinies of  the  whole  organism,  it  is  probable,  find  a 
stronger  echo  in  the  germinal  vessels  than  elsewhere. 

This,  it  must  be  recognised,  is  the  path  on  which 
we  have  to  look  for  the  material  link  between  the  ac- 
quired properties  of  an  organism  and  those  elements 
of  a  germ  that  redevelop  the  parental  qualities. 

You  may  object  that  an  immaterial  something  can- 
not be  determinative  of  the  future  development  of 
germs  so  like  each  other  ;  it  must  rather  be  the  peculiar 
character  of  its  material  composition.     But  I  answer  : 


i8  MEMORY. 

The  curves  and  planes  which  a  mathematician  imag- 
ines, or  accepts  as  imaginable,  are  more  numerous  and 
manifold  than  the  shapes  of  the  organic  world.  But 
if  we  imagine  infinitely  small  portions  of  all  these  pes  - 
sible  curves,  they  will  bear  a  closer  resemblance  to 
each  other  than  germs  do.  Nevertheless,  the  whole 
curve  is  latent  in  each  portion  of  it  and  if  a  mathema- 
tician extends  it  in  its  proper  directions,  it  will  grow 
into  the  peculiar  curve  which  was  determined  by  the 
form  of  its  small  fragmentary  part. 

Therefore  it  is  erroneous  to  declare  that  we  cannot 
imagine  such  minute  differences  in  germs  as  must  here 
be  assumed  by  physiology. 

An  infinitely  minute  dislodgment  of  a  point  or  a 
complex  of  points  in  one  part  of  a  curve  will  alter  the 
law  of  its  entire  course.  Exactly  so,  an  evanescent 
influence  of  the  parental  organism  upon  the  molecular 
structure  of  its  germ  is  sufficient  to  predetermine  its 
whole  future  development. 

Accordingly,  the  reappearance  of  properties  of  the 
parental  organism  in  the  full  grown  filial  organism  can 
be  nothing  else  than  the  reproduction  of  such  pro- 
cesses of  organised  matter  as  the  germ  when  still  in 
the  germinal  vessels  had  taken  part  in ;  the  filial  or- 
ganism remembers,  so  to  say,  those  processes,  and  as 
soon  as  a  same  or  similar  irritation  is  offered,  a  reac- 
tion takes  place  in  it  just  as  formerly  in  the  parental 
organism,  of  which  it  was  then  a  part,  and  whose  des- 
tinies influenced  it. 


MEMORY. 


19 


If  in  a  parental  organism  by  long  habit  or  constant 
practice  something  grows  to  be  second  nature,  so  as 
to  permeate,  be  it  ever  so  feebly,  its  germinal  cells, 
and  if  the  germinal  cells  commence  an  independent 
life,  they  aggrandise  and  grow  till  they  form  a  new 
being,  but  their  single  parts  still  remain  the  substance 
of  the  parental  being,  they  are  bones  of  its  bones,  and 
flesh  of  its  flesh.  If,  then,  the  filial  organisms  repro- 
duce what  they  experienced  as  a  smaller  part  of  a 
greater  whole,  this  fact  is  marvellous  indeed,  but  no 
more  so  than  when  an  old  man  is  surprised  by  remin- 
iscences of  his  earliest  childhood.  Whether  it  still  be 
the  very  same  organised  substance  which  reproduces 
old  experiences,  or  whether  it  be  its  descendant  and 
offspring,  a  part  of  itself,  which  in  the  meantime  ex- 
panded and  grew,  is  a  difference  which,  apparently,  is 
one  of  degree,  not  of  kind.  But,  is  it  not  strange  that 
we  are  engaged  in  considerations  of  how  trifling  in- 
heritances of  the  parental  organism  can  be  reproduced 
in  the  filial  being,  as  if  we  had  forgotten  that  the  filial 
organism  is  nothing  but  one  great  reproduction  of  the 
parental  organism,  even  in  its  minutest  details?  This 
is  because  we  are  so  accustomed  to  accept  their  simi- 
larity as  granted,  that  we  are  astonished  at  finding  a 
child  who  is  to  some  degree  not  quite  like  its  mother, 
and  yet  the  fact  of  its  being  in  so  many  thousand  ways 
like  its  parent  is  much  more  wonderful ! 

If  the  substance  of  a  germ  is  able  to  reproduce 
what  the  parental  organism  has  acquired  during  its 


20  MEMORY. 

individual  life,  how  much  more  will  it  be  able  to  repro- 
duce what  is  innate  in  the  parental  organism  and  has 
been  repeated  through  innumerable  generations  in  the 
same  organised  matter  of  which  the  germ  of  to-day, 
after  all,  is,  and  remains,  but  a  part.  Is  it  then  to  be 
wondered  at,  that  the  things  which  organised  matter 
has  experienced  on  numberless  occasions  are  impressed 
more  strongly  into  the  memory  of  a  germ  than  the  in- 
cidents of  a  single  life  ?  Every  organic  being  which 
lives  to-day,  is  the  latest  link  of  an  immeasurable  series 
of  organic  beings,  of  which  one  rose  into  existence 
from  the  other,  and  one  inherited  part  of  the  acquired 
properties  of  the  other.  The  beginnings  of  this  series, 
it  must  be  assumed,  are  organisms  of  extremest  sim- 
plicity, like  those  which  are  known  to  us  as  organic 
germ-cells.  In  consideration  of  this,  the  whole  series 
of  such  beings  appears  as  the  work  of  the  reproductive 
faculty  which  was  inherent  in  the  substance  of  the 
first  organic  form  with  which  the  whole  development 
started.  When  this  first  germ  divided,  it  bequeathed 
to  its  descendants  its  properties  ;  the  immediate  de- 
scendants added  new  properties  and  every  new  germ 
reproduced  to  a  great  extent  the  modi  operandi  of  its 
ancestors;  part  of  which  grew  feebler,  because  under 
altered  circumstances  their  reproduction  was  no  longer 
elicited. 

Thus  every  organised  being  of  our  present  time  is 
the  product  of  the  unconscious  memory  of  organised 
matter.   Constantly  increasing  and  dividing,  constantly 


MEMORY.  21 

assimilating  new  and  excreting  waste  matter,  con- 
stantly recording  new  experiences  in  its  memories, 
to  be  reproduced  again  and  again,  each  has  taken 
richer  and  more  perfect  shape  the  longer  it  has  lived. 

The  whole  history  of  individual  development,  as 
observed  in  higher  organised  animals,  is,  from  this 
point  of  view,  a  continuous  chain  of  reminiscences  of 
the  evolution  of  all  the  beings  which  form  the  ances- 
tral series  of  the  animal.  A  complicated  perception 
takes  place  by  means  of  a  volatile,  and,  as  it  were, 
superficial  reproduction  of  cerebral  processes  which 
have  been  long  and  carefully  practised ;  exactly  so  a 
growing  germ  passes  quickly  and  summarily  through 
a  series  of  phases  which  were  developed  and  fixed, 
step  by  step,  in  the  memory  of  organised  matter  in 
the  series  of  its  ancestral  beings,  during  a  life  of  in- 
calculable duration.  This  view  was  repeatedly  fore- 
shadowed ;  it  took  shape  in  several  theories  ;  but  was 
only  rightly  understood  by  a  scientist  of  recent  times. 
For  truth  hides  in  different  shapes  before  the  eyes  of 
its  mquisitors,  until  it  is  revealed  to  the  elect. 

A  body,  an  organ,  or  a  cell,  reproduces  simulta- 
neously with  its  interior  and  exterior  shape,  also  its 
functions.  A  chick  which  creeps  out  of  its  shell  at 
once  runs  about,  as  did  its  mother,  when  she,  as  a 
chick,  broke  her  shell.  Think  how  extraordinarily 
complicated  are  the  motions  and  sensations  of  such 
acts  !  Only  consider  the  difficulty  involved  in  the  equi- 
poising of  its  body  in  running,  and  it  will  be  conceded 


22  MEMORY. 

that  the  supposition  of  an  innate  reproductive  faculty 
alone,  can  serve  as  an  explanation  of  these  intricate 
performances.  The  execution  of  a  motion  that  is  ex- 
ercised during  the  greater  part  of  an  individual  life  be- 
comes second  nature,  and  the  actions  of  a  whole  race, 
repeated  over  and  over  again  by  each  member  of  the 
race,  must  also  become  second  nature. 

The  chick  is  not  only  endowed  with  an  inborn 
skill  over  its  motions,  but  possesses,  also,  a  strongly 
developed  perceptive  faculty.  Without  hesitation  it 
picks  up  the  grains  which  are  thrown  to  it.  This  im- 
plies that  it  sees  them,  and  that  it  correctly  judges 
their  position  and  their  distance ;  moreover,  it  has  to 
move  its  head  and  other  limbs  with  great  precision. 
All  these  things  could  not  be  learned  in  the  egg-shell; 
they  were  learned  by  the  many  thousands  of  beings 
which  lived  before  this  chick,  and  of  which  it  is  the 
direct  offspring. 

The  memory  of  organised  matter  is  strikingly  rec- 
ognisable in  this  instance.  Such  a  feeble  irritation  as 
the  rays  produce  which  proceed  from  a  grain  and  fall 
upon  the  retina  of  the  chicken  form  the  occasion  of 
the  reproduction  of  a  complicated  series  of  sensations, 
perceptions,  and  motions,  which  in  this  individual 
have  never  as  yet  been  combined,  and  which,  never- 
theless, from  the  beginning  were  adjusted  with  accu- 
racy and  precision,  as  if  the  animal  itself  had  practised 
them  thousands  of  times.  Such  surprising  perform- 
ances of  animals  are  generally  called  instincts ;  and 


MEMORY.  23 

some  philosophers  have  indulged  in  mystic  explana- 
tions of  instincts.  If  instinct  is  regarded  as  the  result 
of  memory,  or  of  the  reproductive  faculty  of  organised 
matter,  if  we  assume  that  also  the  race  is  endowed 
with  memory,  instinct  is  understood  at  once ;  and  the 
physiologist  is  enabled  to  correlate  and  connect  in- 
stinct with  the  great  series  of  facts  found  to  be  phe- 
nomena of  the  reproductive  faculty.  In  this  way  we 
have  not  yet  gained,  but  we  have  certainly  approached, 
a  physical  explanation  of  the  problem. 

If,  for  instance,  a  caterpillar  changes  into  a  chrys- 
alis, or  if  a  bird  builds  a  nest,  or  a  bee  constructs  a 
cell,  such  animals,  in  obeying  their  instincts,  act  with 
consciousness,  and  are  not  unconscious  machines. 
They  know  to  some  extent  how  to  adapt  their  actions 
to  changed  circumstances  and  are  liable  to  err ;  they 
feel  pleasure  if  their  work  proceeds,  and  displeasure 
if  they  meet  obstacles.  They  learn  by  working,  it 
must  be  assumed,  and  birds,  no  doubt,  build  their 
nests  better  a  second  time  than  the  first.  But  if  animals 
so  easily  find  the  most  practical  means  of  attaining 
their  ends  the  very  first  time,  if  their  motions  are  so 
excellently  and  perfectly  adapted  to  their  purposes,  it 
is  due  to  the  inherited  disposition  of  the  memory  of 
their  nervous  substance,  which  only  awaits  an  occasion 
to  work  in  full  conformity  with  the  situation,  and  re- 
members just  what  is  necessary  for  that  occasion. 

It  is  striking  how  easily  dexterities  are  acquired,  if 
sufficient  limitation  is  exercised.     Onesidedness  pro- 


24  MEMORY. 

duces  virtuosity.  He  who  admires  a  spider  for  spin- 
ning his  web,  should  bear  in  mind  how  limited  his  other 
faculties  are.  Nor  should  he  forget  that  the  spider 
did  not  learn  his  art  himself,  but  that  it  was  acquired 
slowly  by  innumerable  generations  of  spiders,  and  that 
this  art  is  almost  all  they  learned.  Man  takes  to  his 
bow  and  arrows  if  his  nets  fail  to  catch  him  food,  but 
the  spider  must  starve. 

Thus  the  body,  it  is  seen,  and  what  is  of  greater 
import,  the  whole  nervous  system  of  a  newborn  ani- 
mal, is  predetermined  and  predisposed  for  intercourse 
with  the  world  which  it  enters ;  it  is  prepared  to  re- 
spond to  irritations  and  influences  in  the  same  way  as 
this  was  done  by  its  ancestors. 

We  cannot  expect  that  the  brain  and  nervous  sys- 
tem of  man  should  form  an  exception  to  this  rule. 

True,  man  learns  with  difficulty,  while  the  animal 
from  its  very  birth  is,  in  instinct,  matured.  However, 
the  human  brain,  at  birth,  is  at  a  much  greater  dis- 
tance from  the  acme  of  its  development  than  the  brain 
of  an  animal.  Its  growth  not  only  takes  a  longer  time, 
but  is  much  more  marked.  The  human  brain,  we  may 
say,  is  much  younger  when  it  enters  the  world  than 
the  animal  brain.  The  animal  is  born  precocious,  and 
at  once  behaves  precociously.  It  is  like  a  phenomenal 
child  whose  brain  is  overmatured  and,  as  it  were,  too 
old,  so  that  it  is  unable  to  develop  as  luxuriantly  as 
another  brain,  which  is  less  finished  and  inured  to 
work,  but  fresher  and  more  youthful.     The  scope  for 


MEMORY.  25 

individual  development  in  the  case  of  the  human  brain, 
and  generally  of  the  human  body,  is  much  larger,  be- 
cause a  relatively  great  part  of  its  development  is 
relegated  to  the  time  subsequent  to  birth.  It  grows 
under  the  influences  of  its  surroundings,  which  affect 
its  senses,  and  acquires  under  such  circumstances,  in 
a  more  individual  way,  what  an  animal  has  received  in 
the  fixed  formation  of  the  race. 

A  far-reaching  memory,  or  reproductive  faculty, 
we  must  assume,  is  to  be  ascribed  to  the  whole  body, 
as  well  as  particularly  to  the  brain  of  a  newborn  man. 
By  the  help  of  this  memory  he  is  able  to  acquire  the 
attainments  which  were  developed  in  his  ancestors 
some  thousand  times  and  are  necessary  for  his  life, 
much  more  quickly  and  easily.  What  appears  as  in- 
stinct in  animals,  in  man  appears,  in  a  freer  form,  as 
a  predisposition.  True,  ideas  are  not  inborn  in  an 
infant,  but  the  ability  of  ready  and  precise  crystallisa- 
tion of  ideas  from  a  complex  mixture  of  sensations,  is 
due,  not  to  the  labor  of  the  child,  but  to  the  labor  of 
innumerable  ancestors. 

Theories  of  individual  consciousness,  according  to 
which  it  is  assumed  that  each  human  soul  starts  life 
for  itself  and  commences  a  development  of  its  own,  as 
if  the  thousands  of  generations  before  it  had  not  been 
in  existence,  are  in  striking  disagreement  with  the  facts 
of  daily  experience. 

The  realm  of  those  cerebral  processes  which  ele- 
vate and  distinguish  man,  it  must  be  conceded,  is  not 


26  MEMORY. 

of  such  antiquity  as  is  the  province  of  the  more  physi- 
cal necessities.  Hunger  and  the  procreative  impulse 
have  stirred  even  the  oldest  and  simplest  forms  of  or- 
ganic beings.  Accordingly,  organic  substance  has  the 
most  powerful  memory  for  these  stimuli,  as  well  as  for 
their  satisfaction.  The  impulses  and  instincts  rising 
from  them  take  a  firm  hold  even  of  the  man  of  to-day 
with  elemental  power.  Spiritual  life  grows  slowly, 
and  its  most  beautiful  blossoms  belong  to  the  latest 
epochs  of  the  evolutionary  history  of  organised  matter. 
It  is  not  long  that  the  nervous  system  has  been  adorned 
with  the  ornament  of  a  rich  and  grand  brain. 

Oral  and  written  traditions  have  been  called  the 
memory  of  mankind,  and  this  conception  is  true.  But 
beside  it  there  is  another  memory,  which  is  the  repro- 
ductive faculty  of  the  cerebral  substance.  Without  it, 
all  written  and  oral  language  would  be  empty  and 
meaningless  to  later  generations ;  for,  if  the  loftiest 
ideas  were  recorded  a  thousand  times  in  writings  or 
in  oral  traditions,  they  would  be  nothing  to  brains  not 
predisposed  for  them.  They  must  not  only  be  re- 
ceived, they  must  be  reproduced.  If  increasing  cere- 
bral potency  were  not  inherited  simultaneously  with 
inner  and  outer  development  of  the  brain,  with  the 
wealth  of  ideas  which  are  inherited  from  generation  to 
generation,  if  an  increased  faculty  for  the  reproduction 
of  thoughts  did  not  devolve  upon  coming  generations 
simultaneously  with  their  oral  and  written  traditions, 
scripts  and  languages  would  be  useless. 


MEM  OR  V.  27 

The  conscious  memory  of  man  dies  with  his  death  ; 
but  the  unconscious  memory  of  nature  is  faithful  and 
indestructible.  Whoever  has  succeeded  in  impressing 
the  vestiges  of  his  work  upon  it,  will  be  remembered 
forever. 


THE  SPECIFIC  ENERGIES  OF  THE 
NERVOUS  SYSTEM. 


JOHANNES  MUELLER,  the  greatest  physiologist 
of  our  century,  in  his  essays  on  the  senses,  estab- 
lished a  theory  which  is  well  known  as  "  the  theory  of 
the  specific  energies  of  the  sensory  nerves."  I  cannot 
here  recapitulate  his  doctrine  in  his  own  perspicuous 
language,  which  would  be  intelligible  only  to  special- 
ists. But  a  few  sentences  will  sufifice  to  explain  the 
quintessence  of  his  theory  to  any  one  whose  occupa- 
tion prevents  him  from  bestowing  more  than  that  kindly 
interest  upon  physiology  which  this  most  fascinating 
science  awakens  in  the  mind  of  every  educated  man. 
From  the  eye  and  from  the  ear,  from  the  mucous 
membranes  of  the  organs  of  taste  and  smell,  and  from 
the  skin  of  the  whole  body — viz.,  the  organ  of  touch 
and  temperature — proceed  thousands  of  delicate  nerve- 
fibres.  Gradually  uniting,  they  coalesce  into  steadily 
enlarging  bundles,  which  either  lead  directly  to  the 
brain,  or  are  indirectly  connected  with  it  by  the  spinal 
cord.     Through  these  nerve-fibres  the  sensory  organs 


30  THE  SPECIFIC  ENERGIES. 

communicate  with  the  brain,  that  most  wonderful  liv- 
ing structure  which  is  both  the  origin  and  the  product 
of  our  consciousness. 

When  a  vibration  of  ether  irritates  the  nervous 
membrane  of  our  eye  (the  retina),  a  process  ensues, 
the  real  nature  of  which  we  do  not  yet  understand. 
We  only  know  that  the  irritation  is  at  once  transmitted 
to  the  fibres  of  the  optic  nerve,  and  in  its  further  pro- 
gress acts  upon  those  cerebral  parts  into  which  the 
optic  nerve  enters.  As  the  life  of  these  brain-struc- 
tures is  in  close  connexion  with  our  consciousness,  it 
happens  that  when  a  ray  of  light  enters  the  eye,  it 
causes  an  irritation  of  the  nervous  fibres  and  of  the 
cerebral  cells ;  and  thus  we  become  conscious  of  the 
sensations  of  light  and  of  color. 

If,  now,  these  same  rays,  which,  when  entering  the 
eye,  produced  the  sensation  of  light,  fall  upon  the  skin 
of  the  hand,  and  there  irritate  the  delicate  rootlets  of 
the  sensory  nerves,  this  irritation  is  transmitted  through 
the  nerves  and  the  spinal  cord  to  the  brain,  and  in- 
stead of  light  we  are  conscious  of  warmth.  How  is  it 
that  the  same  external  agent  in  one  case  produces 
light,  and  in  the  other  warmth  ? 

Moreover,  the  sensation  of  light  can  be  produced 
in  a  perfectly  dark  room  by  irritating  the  nerves  of  the 
eye  by  an  electric  current ;  and  if  we  pass  the  electric 
current  through  the  auditory  nerve,  we  hear  sounds 
and  noises,  though  the  deepest  silence  surround  us. 
If  we  apply  the  current  to  the  nerves  of  the  skin,  we 


THE  SPECIFIC  ENERGIES.  31 

experience  the  sensation  of  heat  or  cold,  although  not 
in  contact  with  any  cold  or  warm  object.  And  if,  by 
the  very  same  current,  we  excite  the  nerves  of  the 
tongue,  gustatory  sensations  are  produced.  Accord- 
ingly, the  nervous  apparatus  of  each  sensory  organ  re- 
sponds to  the  same  irritation  with  different  sensations. 
And  again  we  ask  :  How  does  precisely  the  same  cause 
produce  such  a  variety  of  effects  ? 

Even  by  the  aid  of  the  microscope  the  anatomist 
has  not  been  able  to  discover  any  essential  difference 
between  the  various  sensory  nerves.  For  instance,  that 
part  of  the  brain  which  produces  the  visual  sensations 
does  not,  in  its  ultimate  structure,  vary  noticeably 
from  those  cerebral  regions  which  produce  sensations 
of  sound  or  temperature.  But  (and  this  is  the  answer 
to  the  problem  in  question)  this  sameness  of  form  is 
not  accompanied  by  a  sameness  of  nature.  The  diverse 
structures  of  the  nervous  system,  the  nerve-cells  and 
the  nerve-fibres,  are  internally  different  in  spite  of  all 
external  similarity,  and  the  diversity  of  the  sensations 
produced  is  a  manifestation  of  such  difference. 

It  is  the  nature  of  the  nervous  substance  in  the 
visual  organ  to  produce  sensations  of  light,  and  only 
such.  It  is  the  bell  which  sounds,  and  not  its  tongue  ; 
and  similarly  it  is  not  the  vibration  of  ether,  but  the 
nerve,  that  produces  light.  No  matter  whether  it  be 
a  ray  of  light, — whether  it  be  a  pressure  or  a  blow  upon 
the  eye,  an  electric  current,  or  any  irritation  what- 
ever,— that  affects  the  nervous  apparatus,  it  invariably 


32  THE  SPECIFIC  ENERGIES. 

manifests  itself  as  light  or  color.  In  the  same  way,  we 
become  conscious  of  the  irritations  of  the  auditory  or- 
gan in  the  form  of  sound  or  noise,  no  matter  what 
their  cause,  which  may  be  aerial  vibrations  or  any 
morbid  irritation  of  the  inner  ear,  or  an  orgasm  of  the 
blood. 

Johannes  Miiller  named  the  inherent  function  of  cer- 
tain nerves  to  communicate  certain  sensations,  which 
could  not  be  produced  otherwise,  to  our  consciousness, 
the  "specific  energy  "  of  those  nerves.  More  than  half 
a  century  has  elapsed  since  this  great  physiologist  de 
veloped  his  theory  in  bold  and  magnificent  propor- 
tions; thus  formulating,  in  scientific  terms,  an  idea, 
the  original  germ  o^  which  lies  buried  in  the  dis- 
tant past,  as  far  back  as  Aristotle.  Johannes  Miiller's 
doctrines  were  re-echoed  in  innumerable  writings,  but 
it  cannot  be  said  that  the  seed  he  sowed  fell  upon  fer- 
tile soil,  or  that  it  was  developed  in  any  essential  fea- 
ture. A  few  partially  successful  attempts  were  made 
to  promote  Miiller's  theory  of  the  sensations  of  color 
and  of  sound  ;  but,  aside  from  that,  his  doctrine  bore 
little  fruit.  On  the  contrary,  it  was  suppressed,  even 
by  Johannes  Miiller's  own  disciples.  It  again  became 
customary  to  regard  all  nerve-fibres  as  having  essen- 
tially the  same  nature,  and  to  suppose  that  the  same 
kind  of  irritation  is  transmitted  in  all  fibres  of  the  vari- 
ous nerves.  The  question  why  the  nerves  of  the  dif- 
ferent sensory  organs  produce  such  various  sensations 
was  either  entirely  abandoned,  or  it  was  deemed  suffi- 


THE  SPECIFIC  ENERGIES.  33 

cient  to  say  that  the  cause  should  be  sought  in  the 
brain,  although  the  same  reasons  which  were  thought 
to  prove  that  all  nerve-fibres  are  of  the  same  nature, 
would  hold  good  also  in  the  case  of  the  cerebral  cells 
and  fibres.  Even  in  some  writings  of  the  present  day 
we  meet  with  authors  who,  confounding  philosophy 
and  physiology,  declare  that  the  theory  of  the  specific 
energies  is  one  of  the  great  aberrations  of  physiology. 

In  consideration  of  this  fact,  permit  me,  as  an  en- 
thusiastic follower,  although  no  personal  disciple,  of 
the  great  scientist,  to  disclose  and  reveal  the  deep 
significance  of  the  great  master's  doctrine,  and  to  show 
that  it  is  the  application  of  a  principle  which  has  been, 
or  surely  will  be,  accepted  in  other  provinces  of  bi- 
ology. 

The  animal  kingdom  exhibits  an  inexhaustible  mul- 
tiplicity of  form,  and  to  a  layman  who  is  not  initiated 
into  the  science  of  biology  it  seems  almost  incredible 
that  living  creatures,  so  manifoldly  different  in  their 
forms  and  habits,  should,  as  germs,  in  the  first  stage 
of  their  development,  be  so  homomorphous  !  As  a 
rule,  even  the  most  experienced  eye,  with  the  assist- 
ance of  every  means  of  scientific  analysis,  would  not 
be  able  to  recognise  in  a  germ  the  animal  into  which 
it  is  going  to  develop.  The  fish  as  well  as  the  bird, 
and  the  insect  as  well  as  man,  so  far  as  we  can  judge 
from  external  appearances,  all  begin  their  lives  as  very 
simple  and  microscopically  small,  spheroidal  struc- 
tures.   Nor  does  this  uniformity  exist  only  for  the  eye ; 


34  THE  SPECIFIC  ENERGIES. 

for  chemical  analysis  resolves  them  all  into  the  same 
ultimate  elements. 

We  ask,  how  is  it  possible  that  totally  different 
forms  can  develop  from  apparently  like  germs  ;  and 
the  answer  is,  that  this  resemblance  of  the  germs  is 
merely  external.  By  the  aid  of  the  most  powerful 
microscopes  we  can  barely  discern  the  roughest  out- 
lines of  their  structures. 

In  the  heavens  whole  systems  of  suns  appear  only 
as  nebulae,  which  even  the  most  powerful  telescopes 
cannot  resolve  into  single  stars.  As  observation  is 
impossible,  we  can  only  surmise  their  structure.  Simi- 
larly the  ultimate  and  exquisitely  delicate  frameworks 
in  the  architecture  of  the  living  substance  of  germs  is 
withdrawn  from  the  observation  of  even  the  minutest 
research.  Could  we  approach  nearer  and  nearer  to 
one  of  these  nebulae,  one  star  after  the  other  would 
emerge  from  the  apparently  homogeneous  mass;  we 
should  see  planets  revolving  around  their  suns,  and 
satellites  about  the  planets.  Thus,  if  with  our  corporeal 
or  intellectual  eye  we  could  penetrate  the  minutest  in- 
ternal structure  of  the  substance  of  germs — if  we  could 
comprehend  the  arrangement  and  motion  of  the  mole- 
cules and  atoms — we  should  discover  that  the  living 
germ-substance  of  each  animal  species  has  its  specific 
properties,  and  the  substance  of  each  single  germ  has 
its  individual  properties  by  virtue  of  which,  in  a  fur- 
ther evolution,  a  special  and  peculiar  type  must  me- 
chanically develop. 


THE  SPECIFIC  ENERGIES. 


35 


Whether  these  internal  variations  of  the  germs  are 
chemical  or  physical,  is,  at  present,  immaterial ;  for 
the  physical  properties  of  a  substance  are  conditioned 
by  their  chemical  qualities,  and  when  we  inquire  into 
the  molecular  and  atomic  structure  of  a  substance,  the 
dividing  line  between  the  domains  of  chemistry  and 
physics  entirely  disappears.  We  cannot,  in  the  im- 
mediate future,  however,  hope  to  find  a  chemical  for- 
mula for  the  individual  germ-substances.  To  reveal 
the  delicate  secret  of  living  matter  by  the  compara- 
tively crude  methods  of  chemistry,  would  be  like  try- 
ing to  explain  the  mechanism  of  a  watch  by  melting  it 
in  a  crucible,  and  examining  the  molten  mass  with  re- 
spect to  its  ingredients. 

As  we  cannot  at  present  solve  the  problem  of  the 
internal  variation  of  the  externally  similar  germ-sub- 
stances, we  must  be  satisfied  with  the  statement  that 
the  germs  of  each  animal  species  possess  an  inherent 
and  innate  faculty — viz.,  a  specific  energy,  which  di- 
rects its  developments  in  a  manner  characteristic  of 
this  animal  and  of  no  other.  Again,  each  single  germ 
possesses  an  individual  energy,  which,  in  addition  to, 
the  normal  features  of  its  species,  secures  an  individual 
character  to  its  future  development. 

Let  us  now  approach  our  problem  from  another 
side.  When  the  naked  eye  is  not  able  to  discern  the 
more  minute  organisation  and  delicate  structure  of  an 
organism,  the  anatomist  employs  the  miscroscope,  and 
a  new  world  of  discernible  facts  is  revealed  to  him. 


36  THE  SPECIFIC  ENERGIES. 

The  apparently  homogeneous  form  dissolves  into  in- 
numerable distinct  structures  ;  millions  of  the  minutest 
separately-existing  beings,  different  in  shape  and  in- 
ternal structure,  compose  a  systematically  arranged 
aggregate,  thus  forming  the  diverse  organs  ;  and  these 
beings,  in  spite  of  the  complicated  interdependence, 
lead  quite  separate  lives,  for  each  single  being  is  an 
animated  centre  of  activity.  The  human  body  does 
not  receive  the  impulse  of  life  like  a  machine  from  one 
point,  but  each  single  atom  of  the  different  organs 
bears  its  vitalising  power  in  itself.  The  current  of 
life  does  not  emanate  from  one  special  part  of  the 
body,  but  all  its  minutest  parts  are  themselves  sources 
of  life.  The  architecture  of  the  human  body,  which 
consists  of  these  elementary  organisms,  or  cells,  as 
they  are  called,  has  often  been  explained.  The  har- 
monious interaction  and  the  division  of  labor  among 
these  innumerable  particles  has  been  compared  to  the 
judiciously  adapted  co-operation  of  the  individual 
members  of  a  well-regulated  community.  As  in  such  a 
community,  so  also  in  the  human  organism,  a  special 
kind  of  work  is  assigned  to  each  group  of  individuals ; 
and,  according  to  the  various  functions,  the  elemen- 
tary organisms  are  differently  formed  ;  but  those  ele- 
ments which  possess  the  properly  so-called  vital  power, 
in  every  respect  exhibit  the  most  striking  resemblance, 
although  it  may  be  hidden  by  and  interwoven  with 
various  less  important  solid  or  fluid  ingredients. 

In  all  living  cells  and  fibres  of  the  different  organs 


THE  SPECIFIC  ENERGIES.  37 

we  encounter  the  same  colorless,  almost  fluid,  soft, 
easily  changeable  substance,  in  the  shape  of  highly 
delicate  threads,  nets,  or  drops.  It  is  the  properly 
vital  element  of  the  cell.  There  the  enigma  of  life  lies 
buried,  for  //  is  the  moving  and  creating  power  in  the 
elementary  organism.  //  produces  the  contraction  of 
muscular  fibres  and  transmits  the  irritation  in  the 
nerve-fibre  ;  it  builds  up  the  solid  and  strong  mass  of 
the  supporting  bone  and  the  tough  fibre  of  the  tendon  ; 
it  shapes  the  feathers  of  the  bird,  the  scales  of  the 
fish,  and  the  horns  of  the  stag. 

Yet  it  is  everywhere  apparently  the  same,  and  if 
it  is  isolated  from  its  proper  sphere  and  surroundings, 
and  considered  by  itself,  the  most  experienced  eye  can- 
not tell  which  of  the  different  functions  was  performed 
by  it. 

Again  we  ask,  hov/  is  it  possible  that  apparently 
equal  causes  produce  such  different  effects.  And  here 
no  one  will  doubt  that  in  spite  of  external  similarity 
the  living  substance  in  the  cells  of  the  individual  or- 
gans is  internally  different ;  and  a  difference  of  func- 
tion necessarily  results  from  this  difference  of  internal 
structure.  It  is  an  innate  function.  The  specific 
energy  of  the  living  substance  in  the  liver  produces 
bile,  as  the  specific  energy  of  the  root  of  a  hair  builds 
up  the  horny  mass  of  hair. 

All  the  innumerable  elementary  beings  or  cells  of 
an  organism  are  the  offspring  of  one  single  germ-cell, 
in  which  the  development  commenced.      By  division, 


38  THE  SPECIFIC  ENERGIES. 

the  first  cell  was  split  in  two.  Although  both  were 
intimately  connected  with  each  other,  they  were  never- 
theless, to  a  certain  extent,  independent  cells.  These 
two  cells  divided  again  and  formed  other  cells,  and  so 
on.  Thus,  by  a  constantly  renewed  formation  of  more 
living  substance  the  number  of  the  elementary  struc- 
tures increases  in  almost  inexhaustible  multiplicity. 
But  in  the  progress  of  multiplication  also  form  and 
arrangement  of  the  cells  are  changed.  They  separate 
into  divers  homogeneous  groups,  each  of  which  differs 
from  the  others  in  character  in  so  far  as  it  performs  a 
special  function.  The  living  substance  is  specialised 
in  the  process  of  development  according  to  its  func- 
tion and  destination.  All  the  united  different  specific"* 
energies  which  later  on  will  separately  develop  to  full 
life  in  its  descendants,  lie  concealed,  although  only 
potentially,  in  the  substance  of  the  germ. 

In  the  light  of  these  considerations  the  diversity  of 
function  in  the  nervous  substance  can  no  longer  sur- 
prise us.  Its  external  similarity  prevents  us  from 
considering  it  as  internally  different,  and  from  claim- 
ing for  it  specific  energies,  according  to  the  doctrine 
of  Johannes  Miiller. 

The  specific  energies  of  the  living  substance  in  the 
different  organs  are  characterised  by  their  chemical  or 
physical  functions;  while  in  the  present  state  of  science 
the  energies  of  the  nervous  substance  can  be  recog- 
nised only  by  the  different  sensations  which  they  pro- 
duce in  our  consciousness.    Our  sensations  and  all  the 


THE  SPECIFIC  ENERGIES.  39 

phenomena  of  consciousness  are  the  psychological  ex- 
pressions of  physiological  processes  or  the  irritations 
of  our  nerves, — especially  of  our  brain.  Vice  versa, 
these  irritations  are  the  material  expression  of  the  pro- 
cesses in  our  soul. 

The  soul  does  not  move  unless,  simultaneous!}', 
the  brain  moves.  Whenever  the  same  sensation  or  the 
same  thought  recurs,  a  certain  physical  process  which 
belongs  to  this  special  sensation  or  thought  is  re- 
peated ;  for  both  are  inseparably  connected.  They  are 
conditioned  by  and  productive  of  each  other.  Accord- 
ingly, from  the  course  of  our  sensations  we  can  draw 
inferences  concerning  the  simultaneous  and  corre- 
sponding course  of  processes  in  the  brain.  The  reso- 
lution of  our  sensations  into  their  various  elements  is 
at  the  same  time  an  analysis  of  the  involved  interac- 
tions of  the  various  elementary  cerebral  functions  or 
irritations. 

For  instance,  let  us  suppose  that  the  great  variety 
of  the  sensations  of  light  and  color  can  be  reduced  to 
a  few  simple  or  elementary  sensations,  to  those  of  the 
principal  colors,  which  by  combining  in  different  pro- 
portions can  produce  innumerable  different  sensations. 
This  fact,  if  proved,  would  justify  the  conclusion  that 
different  kinds  of  elementary  irritations  can  take  place 
also  in  the  nervous  substance  of  the  visual  organ. 
Each  of  them  corresponds  to  one  of  the  elementary 
sensations,  and  the  elementary  irritations  can  be  ar- 
ranged in  a  manner  analogous  to  that  of  the  elemen- 


40 


THE  SPECIFIC  ENERGIES. 


tary  sensations.  Or  similarly,  if  we  succeed  in  reduc- 
ing all  the  many  and  various  gustatory  sensations  to  a 
few  simple  sensations,  we  may  again  justly  infer  that 
a  corresponding  number  of  elementary  irritations  can 
be  produced  in  the  nerve-substance  of  the  tongue. 

Consequently  the  analysis  of  our  sensations  leads 
us  to  recognise  the  fact  that  what  Johannes  Miiller 
summarily  called  the  specific  energy  of  a  sensory  nerve 
may  be  resolved  into  a  certain  number  of  elementary 
irritations.  But  we  need  not  assume  that  a  distinct 
nerve-element  is  a  medium  for  each  simple  irritation. 
The  same  nerve-cell  can  produce  the  sensation  of  heat 
or  of  cold  according  to  the  direction  in  which  its  spe- 
cific energy  is  irritated.  The  same  fibre  of  the  visual 
organ  can  be  irritated  in  different  ways  and  thus  con- 
vey correspondingly  different  sensations  of  color. 

Each  single  kind  of  irritation,  therefore,  does  not 
necessarily  correspond  to  one  and  the  same  nervous 
substance.  The  specific  energy  of  a  certain  nerve- 
element  is  not  merely  a  simple  property,  it  is  not  a 
faculty  which  causes  only  one  kind  of  function,  it  is  a 
multiform  potency. 

The  power  of  specialising  and  individualising  its 
functions  is  an  inborn  quality  of  living  substance,  and 
bears  its  richest  and  most  wonderful  fruit  in  the  ner- 
vous system.  In  this  respect  the  nervous  system  far 
surpasses  all  other  organs. 

One  fibre  of  a  muscle  performs  the  same  function 
as  all  its  other  fibres,  and  even  the  fibres  of  different 


THE  SPECIFIC  ENERGIES.  41 

muscles  possess  essentially  the  very  same  energy.  One 
liver-cell  works  as  all  the  other  liver-cells  do,  and  it 
cannot  work  otherwise.  The  intensity  of  a  function 
may  be  different  in  the  different  fibres  or  cells  of  such 
an  organ,  but  the  kind  of  function  is  common  to  all. 

Not  so  in  the  nervous  system.  The  various  ener- 
gies in  the  various  groups  of  the  nervous  elements  are 
innate.  By  an  innate  faculty  the  optic  nerve  of  the 
new-born  babe  responds  to  the  ray  of  light  which  en- 
ters the  eye  with  a  sensation  of  light,  and  the  nerve  of 
the  skin  responds  to  an  increase  of  temperature  with 
a  sensation  of  warmth. 

The  specific  energy  of  almost  all  other  organs  is 
definitely  fixed  at  the  time  of  birth  and  will  change  in 
the  further  development  of  life  in  degree  only — but 
never  in  character. 

The  muscle-fibre  of  a  babe  contracts  in  the  same 
way,  and  thus  exhibits  the  same  energy,  as  does  the 
muscle-fibre  of  an  adult  person.  The  liver-cell  of  an 
old  man  produces  bile  just  as  the  liver-cell  of  a  child 
does.  The  muscle  as  well  as  the  liver  grows  with  the 
entire  man,  but  the  fibres  and  cells  added  can  always 
perform  only  one  and  the  same  function.  Some  fibres 
and  cells  perish  in  the  course  of  life,  but  those  which 
take  their  place  merely  perform  the  functions  of  the 
replaced  fibres  and  cells. 

Thus  the  innate  energy  of  almost  all  organs  re- 
mains unchanged  throughout  life.  The  individual 
small  cell-organisms  of  which  the  organs  consist,  come 


42  THE  SPECIFIC  ENERGIES. 

and  go,  one  generation  follows  another,  in  some  organs 
more  rapidly  and  in  others  more  slowly.  The  living 
substance  of  each  single  element  is  consumed  and  then 
replaced  by  nutrition,  but  their  faculty  and  activity  al- 
ways remain  the  same.  In  the  nervous  system  all  this 
is  very  different.  Although,  as  a  rule,  the  innate  en- 
ergies of  many  regions,  especially  in  the  peripheral 
nervous  system,  remain  unchanged  throughout  life, 
there  is  in  the  nervous  system  of  a  new-born  babe 
some  living  substance  which  is  ready  to  be  moulded 
for  the  performance  of  this  or  that  function  and  for  the 
development  of  this  or  that  individual  energy. 

Above  all,  the  brain  of  a  new-born  babe  is  not  a 
completed  structure.  It  grows  and  develops  ;  and  if 
the  externally  visible  growth  has  reached  its  limits,  the 
internal  process  of  formation  continues.  Up  to  the 
moment  of  birth  the  nervous  system  with  the  brain  is 
developed  according  to  its  own  inner  law.  Until  then, 
neither  light  nor  sound  nor  any  other  sensory  irritation 
has  affected  the  nerves  and  the  brain  has  been  asleep. 
Afterbirth  thousands  of  new  incitations  at  once  intrude 
from  the  external  world  upon  the  nervous  system.  The 
eye  is  opened  to  the  vibrations  of  ether  and  sound- 
waves obtrude  upon  the  ear,  pressure  and  impact,  cold 
and  warmth  affect  the  skin — thus  placing  the  brain 
which  heretofore  was  left  to  itself,  under  the  influence 
and  discipline  of  the  external  world. 

Before  birth  the  chemical  processes  of  the  nervous 
system,  its  change  of  matter  and  its  growth,  depended 


THE  SPECIFIC  ENERGIES. 


43 


upon  internal  conditions  of  life.  After  birth  the  inci- 
tations  of  the  external  world  excite  the  brain  and  pro- 
duce a  more  vigorous  exchange  of  matter  for  further 
development  and  increase  of  the  living  substance.  The 
further  development,  the  inner  formation  and  cultiva- 
tion henceforth  depend  upon  occurrences  in  the  ex- 
ternal world  which  the  brain  experiences. 

All  living  substance,  especially  nerve-matter,  has 
the  peculiarity  that  every  irritation  produced  in  a  lim- 
ited region  at  once  spreads  to  the  adjoining  parts.  It 
continues  spreading  as  long-  as  it  meets  with  any  sub- 
stance which  is  capable  of  being  similarly  irritated  and 
which,  so  to  speak,  responds  to  such  irritation. 

The  specific  irritation  awakened  in  the  sensory 
nerves  by  external  causes,  is  thus  transmitted  to  the 
virgin  parts  of  the  brain.  Here  in  the  most  youthful 
and  most  docile  living  substance,  the  irritation  termi- 
nates, and  here  every  kind  of  irritation  finds  its  echo. 
For  this  substance  which  possesses  no  innate  and  defi- 
nitely specialised  energy,  has  not  yet  through  the  fre- 
quent repetition  of  a  certain  kind  of  irritation  lost  its 
susceptibility  for  all  other  irritations. 

If  the  virgin  substance  of  the  brain  is  excited  and 
internally  agitated  by  an  irritation  which  has  been 
transmitted  through  the  nerve-fibres  of  the  sensory 
organs,  an  increased  ability  to  reproduce  the  same  kind 
of  irritation  is  acquired  by  a  permanent  change  of  its 
internal  structure.  If  the  sensory  nerve  again  trans- 
mits the  same  irritation,  the   cerebral  substance  re- 


44  THE  SPECIFIC  ENERGIES. 

Spends  to  it  more  easily.  The  oftener  it  is  repeated, 
the  stronger  will  grow  the  inclination  to  reproduce  just 
this  kind  of  irritation.  Through  frequent  repetition, 
one  particular  kind  of  function  becomes,  as  it  were, 
the  second  nature  of  a  single  cerebral  cell,  i.  e.,  the 
cell  acquires  this  special  ability  or  energy.  In  this  way 
the  individual  energies  of  the  cerebral  cells  and  fibres 
are  developed  by  education  on  the  basis  of  the  inher- 
ited dispositions.  Also  the  additional  energy  which 
the  cells  acquire  during  life,  is  transmitted  by  inheri- 
tance to  the  new-formed  cells  which  are  generated  by 
partition.  These  new  cells  can  in  their  turn  develop, 
evolve,  or  modify  the  inherited  energy. 

The  anatomical  arrangement  of  the  brain  is  such 
as  to  place  (single)  parts  of  the  so-called  gray  sub- 
stance into  a  particularly  intimate  relation  with  special 
sensory  nerves.  The  irritation  of  a  sensory  nerve- 
fibre  will  necessarily  seize  upon  and  affect  those  cere- 
bral cells  first  which  are  in  closest  connexion  with  it. 
But  each  cerebral  cell  is  connected  with  other  cerebral 
cells  by  a  net-work  of  most  delicate  nerve-fibres. 

The  irritation  which  enters  from  the  sensory  nerve- 
fibres  into  the  gray  substance  can  advance  (through 
those  cerebral  elements  which  are  excited  first)  in  all 
directions  farther  and  farther  into  the  labyrinth  of  the 
cerebral  cells  and  fibres,  until  at  last  it  dies  out  and 
ceases  sooner  or  later,  or  in  exchange,  calls  forth  new 
irritations,  which,  starting  from  the  brain,  return  to 
the  peripheral  nervous  system. 


THE  SPECIFIC  ENERGIES.  45 

Every  cerebral  element  is  subject  to  the  educating 
influence  of  those  sensory  nerve-fibres  with  which  it  is 
anatomically  connected  and  whose  energies  are  most 
closely  related  to  it.  But  these  single  cerebral  ele- 
ments can  receive  irritations,  although  in  a  weaker 
degree,  also  from  the  adjoining  fibres  of  the  same  sen- 
sory nerve  and  even  from  those  nerve-fibres  which  enter 
the  gray  substance  in  more  remote  parts,  and  which 
originate  in  other  sensory  organs. 

In  this  way  the  cerebral  substance  is  constantly 
permeated  with  many  diverse  irritations,  which  crowd 
upon  it  from  all  the  sensory  regions.  The  cerebral  cell 
will  be  particularly  educated  for  the  qualities  of  these 
irritations,  according  to  its  opportunity  of  easily  and 
repeatedly  receiving  irritation  from  this  or  that  sen- 
sory organ  and  from  such  or  such  a  sensory  nerve- 
fibre.  It  will  acquire  the  faculty  of  reproducing  them 
vigorously,  as  often  as  an  incitation,  be  it  ever  so  weak, 
is  offered. 

Consequently,  every  single  cerebral  element,  in  the 
course  of  its  development  and  under  the  influence  of 
sensory  experience,  attains  an  individual  character. 
And  it  may  be  asserted  that  not  even  two  of  the  in- 
numerable cerebral  cells  are  alike  in  kind  and  degree 
of  individual  energy.  If  one  cerebral  cell  is  destroyed, 
there  would  of  course  be  many  others  which  possess 
in  all  essential  points  the  same  energy,  and  can  by 
ttieir  functions  compensate  its  loss,  but  no  other  cere- 
bral element  could  do  exactly  the  same  work  with  ex- 


46  THE  SPECIFIC  ENERGIES. 

actly  the  same  individual  ability,  with  the  same  ease 
and  exactness;  as  no  man  can,  in  all  respects,  entirely 
replace  another  man. 

Experience  and  practice  rest  upon  this  specialisa- 
tion and  individualisation  of  the  functions  in  the  differ- 
ent cerebral  elements,  and  the  energies  of  the  nervous 
substance  which  are  developed  in  the  course  of  our 
life  are  the  organic  expression  of  our  individual  mem- 
ory. 

The  nervous  system,  and  above  all  the  brain,  is  the 
grand  tool-house  of  consciousness.  Each  one  of  the 
cerebral  elements  is  a  particular  tool.  Consciousness 
may  be  likened  to  a  workingman  whose  tools  gradually 
become  so  numerous,  so  various,  and  so  specialised 
that  he  has  for  every  detail  of  his  work  a  tool  which  is 
specially  adapted  to  perform  just  this  kind  of  work 
most  easily  and  accurately.  If  he  loses  one  of  his 
tools,  he  still  possesses  a  thousand  other  tools  to  do 
the  same  work,  although  with  more  difficulty  and  loss 
of  time.  Should  he  lose  these  thousands  also,  he 
might  retain  hundreds,  with  which  he  can  possibly  do 
his  work  still,  but  the  difficulty  increases.  He  must 
have  lost  a  very  large  number  of  his  tools,  if  certain 
actions  became  absolutely  impossible. 

The  knowledge  of  the  tools  alone  does  not  suffice 
to  ascertain  what  work  is  performed  by  the  tools.  The 
anatomist,  therefore,  will  never  understand  the  laby- 
rinth of  cerebral  cells  and  fibres,  and  the  physiologist 
will  never  comprehend  the  thousand-fold  intertwined 


THE  SPECIFIC  ENERGIES.  47 

actions  of  its  irritations,  unless  they  succeed  in  resolv- 
ing the  phenomena  of  consciousness  into  their  elements 
in  order  to  obtain  from  the  kind  and  strength,  from 
the  progression  and  connexion  of  our  perceptions,  sen- 
sations, and  conceptions,  a  clear  idea  about  the  kind 
and  progression  of  the  material  processes  in  the  brain. 
Without  this  clue  the  brain  will  always  be  a  closed 
book  to  us. 

We  can  indeed  compare  the  brain  to  a  book.  A 
book  is  anatomically  a  number  of  rectangular  white 
leaves,  bound  on  one  side,  and  marked  on  their  pages 
with  numerous  black  spots  of  different  form  and  size. 
Under  a  microscope,  the  leaves  will  be  seen  to  consist 
of  delicate  fibres,  and  the  black  spots  of  minute  black 
granules.  A  chemical  analysis  will  show  that  the 
leaves  are  cellulose,  the  spots  carbon  and  resinous  oil. 
If  all  this  has  been  investigated  and  ascertained  with 
the  utmost  accuracy,  we  do  not  know,  in  the  least, 
why  the  black  spots  are  arranged  just  in  this  and  in 
no  other  way,  why  some  spots  are  large  and  others 
small,  why  some  occur  frequently,  others  rarely,  why 
the  single  leaves  follow  one  another  in  this  and  in  no 
other  order,  and  altogether  what  the  whole  book  really 
means. 

Whoever  wishes  to  know  what  the  book  signifies, 
must  know  what  is  the  function  of  the  specific  energy 
of  each  single  letter  and  of  the  individual  energy  of 
each  single  word — in  short,  he  must  know  how  to 
read. 


48  THE  SPECIFIC  ENERGIES. 

Nothing  can  be  fully  explained  by  a  simile,  and  it 
is  perhaps  dangerous  to  attempt  to  adorn  the  dry  lan- 
guage of  science  with  allegories. 

But  let  the  scientist  wear  his  working  apparel  while 
ploughing  the  field  of  his  science ;  and  when,  on  a 
festal  occasion  he  offers  the  fruits  of  his  labor  to  others, 
he  should  be  welcome  in  a  festive  garment. 


INDEX. 


Acquired  properties,  17. 

Body  and  mind,  functional  interde- 
pendence of,  4-6. 

Book,  the  brain  compared  to  a,  47- 
48. 

Brain,  the  human,  at  birth,  24-25,  42; 
the  soul  moves  concurrently  with, 
39  ;  virgin  parts  of,  43  ;  compared 
to  a  book,  47-48  ;  predisposed  for 
language,  26. 

Caravan,  3. 

Caterpillar,  instincts  of,  23. 

Cerebral,  cells,  individual  energies 
of,  44  ;  elements,  individual  char- 
acter of,  45. 

Chemical  formula  of  germ-substances 
33- 

Chick,  its  organism  a  memory,  21-23. 

Consciousness,  a  datum,  2  ;  a  func- 
tion of  matter,  5-6. 

Cue  needed,  9. 

Curve,  a,  latent  in  its  element,  18. 

Death,  27. 

Discipline  of  the  external  world,  42. 

Echo,  of  organism,  in  germinal  ves- 
sels, 17. 
Empsychosis,  2. 
Enigma  of  life,  37. 
Equal  causes,  apparent,  their  effects, 

37- 
External  world,  discipline  of,  42. 

Filial  organisms  reproduce  old  expe- 
riences, 19. 


Functional  interdependence  of  body 

and  mind,  4-6. 

Functions,  specialisation  of,  46. 

Germinal  vessels,  echo  of   organism 

in,  17. 
Germs,  all  apparently  alike,  34. 
Germ-substances,  chemical   formula 

of,  35- 
Growth,  15,  16. 

Habit,   memory,  synonymous  with 
force  of,  13. 

Idealism,  5. 

Individual,   energies   and   character 

of  the  cerebral  cells,  44,  45. 
Inherited  properties,  16. 
Innate  faculty,  of  the  optic  nerve,  41. 
Interdependence  of  mind  and  body, 

4-6. 

Language,  the  memory  of  mankind, 

26. 
Life,  enigma  of,  37. 
Light,  sensation  of,  30-32. 

Machine,  the  human  body  not  like  a, 
36. 

Materialism,  5. 

Matter,  consciousness  as  a  function 
of,  5- 

Memory,  defined,  7,  11  ;  synonymous 
with  force  of  habit,  13  ;  we  owe  all 
we  are  to,  13  ;  of  germs.  20 ;  of  a 
chick,  21-23  ;  its  general  import,  26 
-27- 

Mind  and  body,  interdependence  of, 4. 


50 


INDEX. 


Mineralogist,  3. 

Mirage,  3. 

Miiller,  Johannes,  29,  32,  38,  40. 

Nerve-fibres,  internally  different,  31. 
Nervous  system,  its  power  of  speciali- 
sation, 40. 
Neurologist,  4. 

Optic  nerve,  innate  faculty  of,  41. 

Philosophy,  i. 

Physicist,  2,  3. 

Physiologist,  3. 

Physiology,  2  et  seq.;  of  the  uncon- 
scious, 12. 

Properties,  inherited,  16;  acquired, 
17;  reappearance  of  parental,  18. 

Psychology,  2,  4. 

Records,  11. 

Reminiscences,  chain  of,  21. 
Reproduction,  faculty  of,  7. 


Sensation  of  light,  30-32. 

Sleep,  a  gap  of  unconsciousness,  10. 

Soul,  moves  concurrently  with  the 
brain,  39. 

Special  research,  i. 

Specialisation  of  functions,  46. 

Specialising,  the  power  of,  in  the  ner- 
vous system,  40. 

Specific  energy,  29,  32  et  seq. 

Stage,  3. 

Toolhouse,  46. 

Unconscious,  life,  i\\  memory,  or- 
ganisms tlie  product  of,  20;  physi- 
ology of  the,  12. 

Unconsciousness,  sleep  a  gap  of,  10. 

Vestiges,  7. 

Virgin  parts  of  the  brain,  43. 

White,  the  idea  of,  8. 
Will,  generally,  6  ;  commander-in- 
chief,  13. 


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